An ice cube at 0°C measures 13.9 cm on a side. It sits on top of a copper block with a square cross section 13.9 cm on a side and a length of 19.1 cm. The block is partially immersed in a large pool of water at 88.5°C. How long does it take the ice cube to melt? Assume that only the part in contact with the copper liquefies; that is, the cube gets shorter as it melts. The density of ice is 0.917 g/cm3.